Page 416 - New Trends in Eco efficient and Recycled Concrete

370 New Trends in Eco-efficient and Recycled Concrete

Figure 13.7 X-ray powder diffraction (XRD) patterns of EAFS and geopolymers with 70:30
fly ash/slag ratio at room temperature and after calcination at 400, 600 and 800 C(Niklioc

et al., 2016). EAFS, Electric arc furnace slag.
ratios: SiO 2 /Al 2 O 3 5 1 and Na 2 O/Al 2 O 3 5 1. Several replacing percentages of MK
by RM from 8% to 25% were tested. The amorphous phase content in geopolymers
was very high for all MK/RM mixtures, being similar to the plain MK geopolymer
(91.5%). The compressive strength reached was similar or lower than that found for
plain MK sample (close to 8 MPa after 28 days of curing). Porosity and water
absorption were in the 48% 51% and 44% 49% ranges, respectively. Kaya and
Soyer-Uzun (2016) tested MK/RM mixes in which the maximum content of RM